Highly Stable Perovskite Solar Cells with Protective Layers Obtained via Interfacial Modification

Abstract

Currently, achieving both high efficiency and long‐term stability is crucial for the successful application of perovskite solar cells (PSCs). Grain boundary (GB) defects significantly impact the stability of PSCs, and passivating these GBs remains a major challenge. Herein, the surfactant dodecyltrimethylammonium chloride (DTAC) is dissolved in low‐polarity chlorobenzene (CB) at 58 °C to modify the interface of MAPbI3 film, and DTAC reacts with MAPbI3 film surface to generate a protective layer that can be covered on the perovskite grains, effectively reducing the expose GBs. Additionally, the hydrophobic alkyl chains of DTA+ and the strong chemical bond between the Cl− and Pb2+ ions further enhance the resistance of the perovskite surface layer to heat, moisture, and oxidation. Due to the passivation of iodine vacancy defects, the photo‐stability of unencapsulated DTAC devices is significantly improved. By passivating surface and GBs defects of the MAPbI3 perovskite crystals, the power conversion efficiency of the low‐temperature carbon‐based PSCs treated by DTAC is 15.03% compared to 13.97% for the control device. This study offers another referable strategy for enhancing the thermal, moisture, light, and oxygen stability of perovskite materials while considering the photovoltaic performance of devices.